import logging
import sys
from typing import Any, Iterable

from django.core.management.base import CommandParser
from django.db import models

from zerver.lib import utils
from zerver.lib.management import CommandError, ZulipBaseCommand
from zerver.models import UserMessage


class Command(ZulipBaseCommand):
    help = """Sets user message flags. Used internally by actions.py. Marks all
    Expects a comma-delimited list of user message ids via stdin, and an EOF to terminate."""

    def add_arguments(self, parser: CommandParser) -> None:
        parser.add_argument('-l', '--for-real',
                            action='store_true',
                            help="Actually change message flags. Default is a dry run.")

        parser.add_argument('-f', '--flag',
                            help="The flag to add of remove")

        parser.add_argument('-o', '--op',
                            help="The operation to do: 'add' or 'remove'")

        parser.add_argument('-u', '--until',
                            dest='all_until',
                            help="Mark all messages <= specific usermessage id")

        parser.add_argument('-m', '--email',
                            help="Email to set messages for")
        self.add_realm_args(parser)

    def handle(self, *args: Any, **options: Any) -> None:
        if not options["flag"] or not options["op"] or not options["email"]:
            raise CommandError("Please specify an operation, a flag and an email")

        op = options['op']
        flag = getattr(UserMessage.flags, options['flag'])
        all_until = options['all_until']
        email = options['email']

        realm = self.get_realm(options)
        user_profile = self.get_user(email, realm)

        if all_until:
            filt = models.Q(id__lte=all_until)
        else:
            filt = models.Q(message__id__in=[mid.strip() for mid in sys.stdin.read().split(',')])
        mids = [m.id for m in
                UserMessage.objects.filter(filt, user_profile=user_profile).order_by('-id')]

        if options["for_real"]:
            sys.stdin.close()
            sys.stdout.close()
            sys.stderr.close()

        def do_update(batch: Iterable[int]) -> None:
            msgs = UserMessage.objects.filter(id__in=batch)
            if op == 'add':
                msgs.update(flags=models.F('flags').bitor(flag))
            elif op == 'remove':
                msgs.update(flags=models.F('flags').bitand(~flag))

        if not options["for_real"]:
            logging.info("Updating %s by %s %s", mids, op, flag)
            logging.info("Dry run completed. Run with --for-real to change message flags.")
            raise CommandError

        utils.run_in_batches(mids, 400, do_update, sleep_time=3)
        exit(0)